Oxidation of Methane to Methanol using a Catalyst Containing a Transition Metal

Abstract

A process for the oxidation of methane to methanol has been developed. The process involves contacting a gas stream, comprising methane, a solvent and an oxidizing agent with a catalyst at oxidation conditions to produce a methyl ester. Finally, the methyl ester is hydrolyzed to yield a methanol product stream. The catalyst comprises a transition metal component such as manganese oxide and an inorganic oxide such as silica. The transition metal component can be dispersed onto the inorganic oxide.

1 . A process for converting methane to methanol comprising contacting a gas stream comprising methane with a catalyst comprising a transition metal component selected from the group consisting of manganese, cobalt, silver, iron and mixtures thereof and an inorganic oxide component, in the presence of an oxidizing agent selected from the group consisting of air and oxygen and a solvent at oxidation conditions to provide a methyl ester compound and hydrolyzing the methyl ester compound at hydrolysis conditions to provide a methanol product stream. 
     
     
         2 . The process of  claim 1  where the oxidation conditions comprise a temperature of about 80° C. to about 200° C., a pressure of about 103 kPa(15 psia) to about 6867 kPa (1000 psia), a contact time of about 1 minute to about 24 hrs and an oxidizing agent concentration from about 1 mol % to about 100 mol %. 
     
     
         3 . The process of  claim 1  where the hydrolysis conditions include a temperature of about 20° C. to about 200° C. and a pressure of about 103 kPa (15 psi) to about 1030 kPa (150 psi) and at least a stoichiometric amount of water. 
     
     
         4 . The process of  claim 1  further comprising carrying out the hydrolysis in the presence of a catalyst selected from the group consisting of acidic catalysts and basic catalysts. 
     
     
         5 . The process of  claim 4  where the acidic catalyst is selected from the group consisting of hydrochloric acid, sulfuric acid, trifluoroacetic acid, toluene sulfonic acid, acidic alumina, silica-alumina, sulfated zirconia, acidic ion exchange resins and mixtures thereof. 
     
     
         6 . The process of  claim 4  where the basic catalyst is selected from the group consisting of sodium hydroxide, lithium hydroxide, potassium hydroxide and hydrotalcite. 
     
     
         7 . The process of  claim 1  where the transition metal component comprises a compound selected from the group consisting of metal oxides, metal salts, organometallic compounds, and mixtures thereof. 
     
     
         8 . The process of  claim 7  where the transition metal compounds are selected from the group consisting of K 2 Mn 4 P 3 O 16 , MnPO 4 . H 2 O, Na 2 Mn 2 P 2 O 9 .H 2 O, KMn 8 O 16 , Mn(II)trifluoroacetate, Mn(II) acetate, Mn(III)acetate, Co 2 O 3 , Co(II) Acetate, AgO, Ag(I)trifluoroacetate, Fe 2 O 3 , (FeMn)PO 4  and mixtures thereof. 
     
     
         9 . The process of  claim 1  where the transition metal component is deposited onto the inorganic oxide. 
     
     
         10 . The process of  claim 1  where the inorganic oxide is selected from the group consisting of silica, aluminas, aluminum phosphate, ceria, magnesium oxide, lanthanum oxide, molecular sieves and mixtures thereof. 
     
     
         11 . The process of  claim 1  where the oxidizing agent is intermittently added. 
     
     
         12 . The process of  claim 1  where the solvent is selected from the group consisting of trifluoroacetic acid, trifluoroacetic anhydride, pentafluoropropionic acid, acetic acid, super critical carbon dioxide, sulfuric acid, sulfur trioxide, trifluoromethanesulfonic acid, methanesulfonic acid and mixtures thereof. 
     
     
         13 . The process of  claim 1  where the process is a batch process. 
     
     
         14 . The process of  claim 1  where the process is a continuous process. 
     
     
         15 . The process of  claim 11  where the oxidizing agent is air.